Metals and Non-Metals — Science STD 10 — Question

Using the phenomenon of scattering of light, explain why there is a difference in the colour of the sun as it appears during sunrise and at noon.

Some of the important fossils which have been studied are those of organisms X, Y and Z. X were marine arthropods which were common between 400 to 600 million years ago. Y were the invertebrate animals (molluscs) with a flat, coiled, spiral shell which lived in the sea about 180 million years ago. Z are the extinct carnivorous or herbivorous reptiles which appeared on the earth about 250 million years ago and became extinct about 65 million years ago. What are X, Y and Z?

1. Give the names and formulae of one metal chloride and one non-metal chloride.
2. State an important property in which these metal chloride and non-metal chloride differ.
3. Why do they differ in this property?

Describe the New Cartesian Sign Convention used in optics. Draw a labelled diagram to illustrate this sign convention.

What is ‘‘dispersion of white light’’? Draw a labelled diagram to illustrate the recombination of the spectrum of white light. Why is it essential that the two prisms used for the purpose should be identical and placed in an inverted position with respect to each other?

What would be the effect on the resistance of a metal wire of:

1. Increasing its length?
2. Increasing its diameter?
3. Increasing its temperature?

In what way can biodegradable substances be used by farmers?

What substances are contained in gastric juice? What are their functions?

An object 2cm tall stands on the principal axis of a converging lens of focal length 8cm. Find the position, nature and size of the image formed if the object is:

1. 12cm from the lens.
2. 6 cm from the lens.